Hydrangea macrophylla plant named ‘HYMMAD II’

ABSTRACT

Hydrangea macrophylla,  ‘Hymmad II’ has multi-rowed pink lacecap inflorescences that maintain the color in the presence and absence of aluminum. Inflorescences mature to a beautiful lime green. The habit is rounded with strong purple-black stems that hold the flowers upright. The lustrous, leathery, bullate, black-green leaves are highly mildew resistant.

Botanical classification: Hydrangea macrophylla.

Varietal denomination: ‘Hymmad II’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Hydrangea macrophylla, a member of the Hydrangeaceae family, hereinafter referred to as ‘Hymmad II’. This cultivar is grown primarily as an ornamental for landscape use and for use as a potted plant, fresh cut and dried flowers. The cultivar originated from open-pollination of Hydrangea macrophylla ‘Nigra’ (also know as ‘Mandschurica’) (non-patented, the pollen donor being unknown. It was selected at the University of Georgia, Athens, Ga. in 2002, from the progeny seedlings of this open pollination by continued evaluation for large, triple-rowed, pink sepals surrounding the center of fertile, violet-purple flowers, stout purple-black stems, increased mildew resistance, and improved leaf and flower characteristics.

‘Hymmad II’ is distinguished from its female parent ‘Nigra’, which has a pink or blue mophead inflorescence, by its pink lacecap inflorescence that does not change color in the absence or presence of aluminum (Al). The sepals (sterile florets) emerge green around the periphery of the inflorescence, open pink, and mature to lime green, maintaining the latter color when utilized as dried flowers. Inflorescences are more resistant to water stress and do not wilt under high heat. ‘Hymmad II’ has lustrous, more leathery, bullate, black-green leaves than ‘Nigra’. ‘Hymmad II’ had slight mildew in early fall, whereas in side-by-side comparisons, ‘Nigra’ was 100% infected by mildew. The thick, stout stems of ‘Hymmad II’ hold the inflorescence upright, without splaying. ‘Nigra’ inflorescences are mopheads and weigh the stems to the ground. ‘Hymmad II’ produces flowers from terminal and lateral buds, whereas ‘Nigra’ only produces them from terminal buds.

SUMMARY OF THE INVENTION

The following traits have been observed and represent the characteristics of the new Cultivar. In combination these characteristics distinguish ‘Hymmad II’ from all other varieties in commerce known to the inventor.

-   -   1) Pink-mauve flowers (sepals) are not affected by the presence         or absence of Al and hold the color until maturation.     -   2) At maturation, sepals turn lime green and dry to this color.     -   3) Triple rows of sepals around the periphery of the         inflorescence create a showier lacecap than typical for the         species.     -   4) Inflorescences are more resistant to heat and drought and do         not wilt under moderate stress.     -   5) Leaves are more heat and drought resistant than ‘Bailmer’         U.S. Plant Pat. No. 15,298) and, growing side-by-side do not         flag (wilt) like the latter.     -   6) Rounded habit with thick, stout purple-black stems that hold         the inflorescences upright.     -   7) Lustrous, leathery, bullate, black-green leaves.     -   8) Leaves display high mildew resistance. ‘Nigra’, in Athens,         Ga., is typically defoliated by powdery mildew in October while         ‘Hymmad II’ is completely foliated with only slight mildew on         the older leaves.

‘Hymmad II’ has been asexually propagated in Athens, Ga. since 2002. The characteristics of the cultivar have been stable and reproduced true-to-type in successive vegetative generations.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

FIG. 1 shows lustrous black-green leaves on thick, purple-black stem.

FIG. 2 shows inflorescence opening showing emerging green sepals and green-pink fertile flower buds.

FIG. 3 shows peak inflorescence showing triple-rowed pink sepals and green-purple fertile flower buds.

FIG. 4 shows inflorescence with maturing green sepals.

BOTANICAL DESCRIPTION OF THE PLANT

A detailed description of Hydrangea macrophylla ‘Hymmad II’ follows. Colors are based on The Royal Horticultural Colour Chart (1995). All measurements/characteristics were taken from 2-year-old plants growing in 11.8 liter containers under 50% shade at Athens, Ga., USDA Zone 7. Measurements of leaf/stem and floral characteristics are based on 10 to 20 samples. The presence of Al means that the plant was treated with aluminum sulphate (42 g per 3.8 liters of water) applied as a soil drench when flower buds were visible.

-   Plant: The plant has an upright, rounded growth habit, with many     upright branches from the base, attaining a size of 30 cm high by 60     cm wide after 2 years. -   Stems: Current year stems are round, averaging 5 mm in diameter,     with no pubescence, and are Greyed-Purple 187A in color. The average     internode length is 10.5 cm. Second year stems are round, 10 mm in     diameter, not pubescent and Greyed-Yellow 161D, Greyed-Orange 165B,     Greyed-Brown N199C in color. -   Vegetative buds: The willow type vegetative buds are in an opposite     arrangement, 2 per node, at a 45° angle to the stem. They are     globose in shape, 8 mm by 4 mm, and have 2 scales which are     Greyed-Brown 199C in color. The bud color is Greyed-Purple 183B. -   Flower buds: The flower buds are round in shape with no pubescence,     4 mm long by 4 mm wide by 3 mm deep and Violet-Blue 98C in presence     of Al, and Purple 76C in absence of Al. They develop in the early     summer. -   Leaf: The leaves, in opposite arrangement, are ovate in shape with     acute base and acuminate apex and serrulate margin. The mature leaf     is 9.9 cm long by 7.5 cm wide, very thick and leathery and very     waxy. It has no pubescence. The color of the emerging leaf is     yellow-Green 144A on the upper surface and Yellow-Green 144C on the     lower surface, maturing to Green 139A on the upper surface and Green     137B on the lower. The venation is pinnate, with Yellow-Green 144D     veins. The petioles average 2 cm long and 3 mm in diameter are     grooved above and rounded below, with no pubescence, and are     Yellow-Green 146B in color. -   Inflorescence: The bloom period is mid May to the end of June in     Athens, Ga., and the mature, green inflorescences persist into the     fall. The corymb lacecap inflorescence contains 3 rows of sterile     florets, often intermingled with fertile flowers, around the center     of fertile flowers. It is oval in cross-section, 12.5 cm by 14.7 cm,     and 7 cm deep. There are on average 6 inflorescences per 2-year-old     plant, and the inflorescence contains 1368 flowers. -   Sterile florets: There are 4 sepals per floret, and an average of 20     florets per inflorescence. The sepal is ovoid to round in shape with     rounded apex and acute base and mainly entire margin with an     occasional serration. The texture is smooth with no pubescence. They     are 25 mm long by 23 mm wide. At peak of bloom the upper surface is     Violet 84C, both in presence and absence of Al, aging to     Yellow-Green 145B, and the lower surface is White N155D, both in     presence and absence of Al, aging to Yellow-Green 145B. The peduncle     is finely pubescent, 1 cm long and Greyed-Purple 184B in color, both     in presence and absence of Al. -   Fertile flowers: The 5 petals are ovate in shape, with acute apex,     truncate base and an entire margin. They are 4 mm in length by 2 mm     wide, with a smooth texture and no pubescence. The color of the     upper surface is Violet-Blue 98B in presence of Al, and Purple 75B     with Violet 85B at base in absence of Al. The lower surface is     Violet-Blue 98D with Violet-Blue 98B at base and along margins in     presence of Al, and Purple 75C with Violet 85B at base in absence of     Al. The pedicle is 2 mm long, smooth, and Red-Purple 60A in presence     of Al, and Red-Purple 58A in absence of Al. There are 10 stamens,     the anthers being 1 mm long by 1 mm wide and Violet-Blue 98C in     presence of Al, and Purple 76B in absence of Al. The filament is 3     mm long by 0.3 mm wide and Violet-Blue 98B/Violet-Blue 94C in     presence of Al, and Red-Purple N74D in absence of Al. The superior     pistil is globose in shape, 3 mm long by 2 mm wide with no     pubescence. There are 3 to 4 oval stigmas per flower, finely     pubescence and Violet-Blue 90A in presence of Al, and Purple-Violet     N80C in absence of Al. The style is tubular in shape, 1 mm long with     no pubescence and Violet-Blue 94D in presence of Al, and Purple 75B     in absence of Al. -   Fruit: The fruit is a capsule, oval in shape, 4 mm long by 3 mm     wide, and Yellow-Green 143A in color. Seed: The seeds average 0.5 mm     long by 0.25 mm wide and are Greyed-Orange 164C in color. 

1. A new and distinct variety of Hydrangea macrophylla plant substantially as herein described and illustrated. 